This invention relates to a system of ultrasonic diagnosis and therapy. In particular, this invention relates to the use of ultrasonics for providing in real-time, cross-sectional and 3-D images of an organ for diagnosis and utilizing the same system to treat disorders by non-invasive means. The invention combines two components, a real-time ultrasonic piezoelectric diagnosis unit and a high intensity, focussed therapeutic ultrasonic sub-system.
Ultrasonic transducers used for non invasive therapeutic applications are known in the art. Such ultrasonic transducer assemblies generally comprise a housing and a transducer mounted within the housing for radiating a converging beam of acoustic energy in response to an applied electrical signal. The beam of acoustic energy converges to a focal point which is usually the therapeutic point of application. Such devices have found utilization in the treatment of disorders of the eye or other organs by non-invasive means.
The applications of ultrasound in the field of ophthalmology is discussed, for example, in Coleman et al. "Therapeutic Ultrasound in the Production of Ocular Lesions", Amer. J. of Ophthal., Vol. 86, No. 2, pp. 185-192, 1978 and Coleman, et al. "Applications of Therapeutic Ultrasound in Ophthalmology" Progress in Medical Ultrasound, pp. 263-270 (1981). The use of a paraxial diagnostic transducer is disclosed to allow manual positioning of the therapeutic focus within the targeted zone. The position of the therapeutic focus within the targeted zone is monitored by observation of a diagnostic B-scan or A-scan display. Once positioned, the therapeutic transducer is actuated for the desired application of ultrasound for example the production of lesions.
U.S. Pat. No. 3,735,755 discloses a complete ultrasonic system employing a transducer assembly used by the operator for both display and treatment. The complicated system disclosed therein is cumbersome and does not provide the level of data needed to perform difficult procedures in real-time in a simple clinical setting.
B-scan diagnosis devices and transducers are also discussed in U.S. Pat. Nos. 4,141,347 and 4,237,901.
Ultrasonic techniques have also been employed successfully in lithotropsy. In systems using acoustic shock wave generation the transducer may be employed together with an ultrasonic positioning unit. The extent of therapeutic action is determined by subsequent X-ray. Alternatively, a separate ultrasonic scanner may be employed in a paraxial arrangement for positioning.
Reference is made to U.S. Pat. No. 4,617,931 which relates to a transducer for producing shock waves and an auxiliary ultrasonic transducer disposed paraxially and mechanically swept. Use of the piezoelectric transducer itself for positioning is disclosed in Ziegler et al, "Extracorporeal Piezoelectric Lithotropsy". A commercial system employing B-scan and a lithotropic transducer is the Piezolith 2200 manufactured by Richard Wolf GMBH and described in Riedlinger et al, "Die Zertrummerung von Hierensteinen durch piezoelektrisch erzengte Hochonergie-Schallpulse", urologe [A] (1986) 25:188-192. Reference is also made DE 27 22 252 Al and a Dornier system technical description entitled "Entwicklung eines Verfahrens zur beruhrungsfreien Zerkleinerung von Hierensteinen durch StoBwellen" (1976).
Reference is made to U.S. Pat. No. 4,484,569, entitled "Ultrasonic Diagnostic and Therapeutic Transducer Assembly and Method for Using", commonly assigned, which is expressly incorporated herein by reference. The system described therein allows the use of the single transducer assembly to generate acoustic energy for purposes of either diagnosis by generating A-scan images or, to use ultrasonic beams for non-invasive treatment.
Using the technology of the '569 patent, with the patient properly prepared, the transducer assembly that houses the therapeutic and diagnostic transducers is first used for diagnostic purposes to allow displays for the practitioner so that the organ under scrutiny may be explored. Once this diagnostic phase is completed, ultrasonic energy from the same transducer assembly may be used to perform non-invasive treatment of the organ. The power to the therapeutic transducer produces a burst of high energy acoustic radiation applied to the site requiring treatment. Following the application of a therapeutic beam, the initial diagnostic transducer may be used to provide A-scan and ultrasonic echoes to determine changes in tissue characteristics. The process is then repeated on an iterative basis until the treatment has been completed.
The '569 patent also allows for visual positioning of the therapy beam by the use of a light beam radiated through the transducer by means of a fiber optic conduit.
While this system offers important advantages in the treatment of tissue disorders, especially those of the eye, a need exists to provide viewing and data collection of diagnostic information for 2- and 3-dimensional positioning, i.e., aiming and for information concurrent with therapeutic application of ultrasound. Concurrent monitoring would allow the practitioner to apply intense ultrasound to tissue on a real-time basis, and judge the condition of the insonified tissue during irradiation. This in turn would permit a determination of whether further treatments are called for and the precise location for such treatment.
It is therefore an object of this invention to provide for a new and improved ultrasonic system which allows for the concurrent diagnosis and therapeutic application of ultrasonic waves to tissue.
An important object of this invention is to provide a system of three dimensional ultrasonic echo image generation.
Yet another object of this invention is to provide a system of real-time monitoring of ultrasound therapy to assess the dynamic response within tissue during and immediately after insonification.
A further object of this invention is to provide for an ultrasonic system wherein viewing and data collection of diagnostic information occur concurrently with therapeutic applications.
A still further object of this invention is to provide a system of visual image display depicting tissue regions that are likely to be modified by selecting specific exposure conditions such as time, intensity, beam profile, frequency and the like.